CVE-2026-21521

{"id": "CVE-2026-21521", "cveTags": [{"tags": ["exclusively-hosted-service"], "sourceIdentifier": "secure@microsoft.com"}], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "secure@microsoft.com", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 7.4, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 4.0, "exploitabilityScore": 2.8}]}, "published": "2026-01-22T23:15:57.823", "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21521", "tags": ["Vendor Advisory"], "source": "secure@microsoft.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "secure@microsoft.com", "description": [{"lang": "en", "value": "CWE-150"}]}], "descriptions": [{"lang": "en", "value": "Improper neutralization of escape, meta, or control sequences in Copilot allows an unauthorized attacker to disclose information over a network."}], "lastModified": "2026-02-02T13:30:53.350", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:microsoft:365_word_copilot:-:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3A538269-3D01-41B4-B8B1-B70D8514D336"}], "operator": "OR"}]}], "sourceIdentifier": "secure@microsoft.com"}